Instructions

To make the blackberry sauce:

1.  Put the blackberries, sugar, water, and crème de mûre (if using) in a small saucepan and bring to a boil on a medium heat. Let bubble for 3 minutes. 
2. In a small bowl, stir together the lemon juice and cornstarch and pour into the blackberry sauce. Stir to combine
3. Simmer for 10 minutes, then remove from the heat and allow to cool completely. 

To make the brownies:

1. Preheat the oven to 350F/180C and line a 9x13" brownie pan with parchment paper, leave lots of overhang at the ends for easy removal.
2. Melt the butter, sugar and chocolate together. Leave to cool slightly. 
3. Put the flour, cocoa powder, salt, and baking powder in a bowl and whisk together. Set aside
4. Beat the eggs and brown sugar together. Beat in the vanilla, coffee, and crème de mûre (if using). Beat in the melted chocolate mixture. 
5. Pour into the prepared pan and bake for 20 minutes, until the top is just set (the inside will still be raw batter). 
6. Reduce the oven temperature to 325F/160C

To make the cheesecake:

1. Beat together the cream cheese and sugar until combined. Beat in the eggs one at a time. 
2. Stir in the yogurt and vanilla. 
3. Stir in 3 tbsp of the cooled blackberry sauce
4. Carefully spoon the cheesecake over the half baked brownies (carefully, so you don't break the set top). 
5. Spoon the rest of the blackberry sauce over the top, and swirl with a blunt knife (again, being careful not to break the set top of the brownies). 
6. Bake at 325F/160C for 40 minutes, or until the cheesecake is set and slightly springy to touch.
7. Cool completely in the pan, on a wire rack, then chill in the fridge for at least 6 hours. 
8. Cut into squares to serve